Emiliano Sala's former club Nantes are demanding that Cardiff City pay the transfer fee agreed for the player, according to reports.
Sala and pilot David Ibbotson were on board a plane that disappeared over the English Channel on January 21.
A privately funded search located the wreckage this week and investigators have said that work is continuing on the operation to recover the body located in the wreck.
Sala signed for Cardiff for £15m in January from French club Nantes.
Now, BBC Wales reports that Nantes are "threatening legal action if they do not receive a payment within 10 days".
The report says that the transfer fee is due to be paid in instalments over three years.
A Cardiff source told the BBC that they will honour the contract but "not until they have clarified 'all the facts".
Sala had been in France to say goodbye to his teammates in Nantes before departing for Cardiff in the plane when it disappeared.
Cardiff has paid tribute to Sala since the tragic disappearance, and won an emotionally-charged home clash with Bournemouth 2-0 on Saturday – their first game at home since the incident.
City boss Neil Warnock praised his players after the win, which was the club's first of 2019.
"I can’t be more proud. If we didn’t get another point this year, I’d still think the players have been amazing," he said.